If WS-Man datacollection group with resource-type is used, only the last resource is stored.
Please see attached collect.log.

Used the following wsman collection group and resource type:

<resourceType name="WinPagefileIndex" label="Pagefile - WS" resourceLabel="Pagefile (${PagefileName})">
<persistenceSelectorStrategy class="org.opennms.netmgt.collection.support.PersistAllSelectorStrategy"/>
<storageStrategy class="org.opennms.netmgt.dao.support.SiblingColumnStorageStrategy">
<parameter key="sibling-column-name" value="PagefileName" />
<parameter key="replace-all" value="s/\s//" />
<parameter key="replace-all" value="s/:/_/" />
<parameter key="replace-all" value="s/\./_/" />
<parameter key="replace-all" value="s/
/_/" />
</storageStrategy>
</resourceType>

<group name="windows-pagefile"
resource-uri="http://schemas.microsoft.com/wbem/wsman/1/wmi/root/cimv2/Win32_PageFileUsage"
resource-type="WinPagefileIndex">
<attrib name="Name" alias="PagefileName" type="String"/>
<attrib name="AllocatedBaseSize" alias="PagefileAllocSize" type="Gauge"/>
<attrib name="CurrentUsage" alias="PagefileCurUsage" type="Gauge"/>
</group>